Reference may be made to the following U.S. Pat. Nos. of interest: 3,869,023; 3,895,690; 4,024,930; 4,085,821; 4,271,930; 4,274,509; 4,368,803.
Automatic chain lubricating devices are used extensively in industry for automatically applying lubricant under pressure to a particular point of the chain system. The various types of commercially available chain lubricating devices can be classified as either a moving lubricator nozzle device or fixed lubricator nozzle device.
Fixed lubricator nozzle devices include fixed lubricator nozzles rigidly mounted to the conveyor track with the lubricant being timed for application to the desired conveyor point by means of a control system actuated by a sensor which detects passage of a particular portion of the conveyor.
In contrast, in moving lubricator nozzle devices, the moving nozzle is controlled in a path to advantageously place the nozzle and the lubricant shot near the conveyor point desired to be lubricated while avoiding conveyor attachments which could damage the nozzles. Such moving nozzle devices utilize a mechanical interface to synchronize movement of the nozzle to the conveyor. While such moving lubricator nozzle systems are more accurate than fixed lubricator nozzle systems, they generally require more maintenance due to the increased number of components and to the complexity of the required mechanical interface equipment.
Commercially available moving nozzle lubricators are known. One such mechanism manufactured by Madison-Kipp Corporation of Madison, Wis., assignee of the present invention, moves the lubricating nozzles in a cycloidal path, the points of which pass above a conveyor chain. The lubricating nozzles are attached to a caterpillar chain mechanism which properly synchronizes the cycloidal period to the speed of the conveyor chain. The caterpillar chain mechanism is automatically engaged with the conveyor chain by a pneumatically actuated cylinder when a lubrication cycle is necessary. A plate mounting the nozzles physically actuates a fluid trip valve when the nozzle is moved into position and enables the lubricating fluid to be delivered to the nozzle. This moving nozzle lubricator device functions satisfactorily, but is complex and has many components which require maintenance.
The second commercially available moving nozzle lubricator is similar to the aforementioned Madison-Kipp Corporation device in that it also employs a caterpillar chain synchronizing mechanism and physical actuation of a fluid trip valve, but with the cycloidal action modified to effect a longer "dwell time"--i.e., the time during which the moving nozzle is in position adjacent the desired conveyor point to be lubricated. The modification, however, makes this second commercial unit even more mechanically complex than the first mentioned commercial unit and therefore increases rather than reduces the number of components requiring maintenance.
In a third commercially available moving nozzle lubricator, nozzles are formed by drilling apertures into sprocket teeth which engage the chain during chain movement. A fluid trip valve is physically actuated when the sprocket teeth are moved during positioning. Although the nozzles formed by the apertures are close to the chain, the axial direction of the nozzles are not toward the desired target area to be lubricated on the chain. Also, since most conveyor chains are in an industrial environment subject to dust and dirt, the nozzles can become quickly blocked, requiring periodic maintenance.
Accordingly, it is desired to provide a lubricating device and in particular a moving nozzle lubricating device which obviates the need for caterpillar chains and sprockets and thereby reduces maintenance problems. In addition, it is desired to provide such a device having as few components as possible in order to reduce the complexity of currently available commercial devices of this type.
It is also desired to provide an automated lubricator system which can reliably deliver clean shots of lubricating fluid and substantially prevent lubricating fluid drippage from the nozzles. Presently, air in the fluid lines, the normal expansion of fluid and of the system components, a "pumping action" during shuttling or deactivation of the actuable fluid solenoid valves normally employed, and the inherent interconnection of all three ports of such solenoid valves at an instantaneous point in time during operation since they are an imperfect diverter valve, all contribute to reduce the ability to obtain clean shots and to enhance fluid drippage. The solution to these problems is made more complex due to the small volume amount of fluid delivered in each shot--ranging from about 0.002 to 0.004 cu. in.